Tuner



F. WOODS Nov. 24, 1936.

TUNER Filed Dec. 29, 1931 2 Sheets-Sheet 1 INVENTOR FRED WOODS ATTORNEY F. wooDs Nov. 24, 1936.

TUNER Filed Dec. 29, 193.1 2 Sheets-Sheet 2 INVENTOR FRED wooos 4 ATTORNEY Patented Nov. 24, 19 36 PATENT OFFICE TUNER Fred Woods, Richmond, Surrey, England, as-

signor to Radio Corporation of America, a cor-' poration of Delaware Application December 29, 1931, Serial No. 583,631 In Great Britain December 29, 1930 15 Claims. (01. 171-119) This invention relates to radio and other high frequency receivers, and more particularly to socalled multi-range receivers, i. e. receivers adapted to be operated over a plurality of tuning ranges.

The invention has for its object to provide a multi-range radio or other high frequency receiver, whereby the necessary switching operations to change the receiver over from one wave length range to another may be effected in a simple and rapid manner, and wherein the number of external connections necessitated by such switchings may be reduced to a minimum.

In carrying out the invention, use is made of multiple winding inductance units of the kind in which the body of the inductance unit, which body carries the windings, is movably mounted, the windings terminating in contact devices which are associated selectively with co-operating .contact devices, according to the position into which the said body is moved.

According to this invention a multi-range radio or other high frequency receiver comprises a plurality of movably mounted inductance units, each having a plurality of sets of windings (each set of windings being appropriate to one tuning range), the windings of each unit terminating in contact devices adapted to co-operate selectively with appropriate switch members, according to the position into which the unit is moved, and means are provided for actuating all said units in common, so that by operating the common actuating meansali said units may be moved together into positions in which the windings in circuit are all appropriate to a desired wave length range.

The invention is illustrated in the drawings accompanying the specification in which Figure 1 is a simplified wiring diagram of an amplifier, suitable for use in connection with a direction finding installation; Figure 2 is a schematic elevation showing the mechanical arrangement for operating the multi-windinginductance units employed in the amplifier shown in Figure 1; Figure 2a is an elevation similar to that of Figure 2;

Figure 2a, however, shows in detail a portion of Figure 3; however in Figure 30; details of the mechanism for short circuiting the unused windings' of the inductance units is shown; and Figure 4 is an end view of Figure 2 showing the common control knob and associated pointer.

Referring to the drawings, input signals received at I are applied through a transformer between the control grid and cathode of a high frequency amplifying screened gridvalve VI. The transformer consists of two portions; a primary portion 2 and a secondary portion 4. On the primary portion are provided three primary windings I, 3 and 5, the winding l terminating in contacts C2, and C3, and the winding 3 terminating in contacts Cl and C4. The winding 5 also terminates in contacts as shown but in order to simplify the description of my novel inductance changing system, two different transformer systems only will be described. The manner in which the additional transformer systems are placed in circuit will be apparent from the description given in connection with the two transformer systems. The secondary portion 4 simi- 20 larly carries three windings 6, 8 and ill, of which 6 and 8 terminate respectively in contacts C6, C9 and C5 and C8. Each primary winding is appropriate to one wave length range, as also is each secondary winding. The portions 2 and 4 con- 25 stitute a mechanical unit which is rotatably mounted, and fixed switch members S I, S2, S3, S3 are provided so that in the position shown in Figure l, the windings l and 6 are in circuit, while, by rotating the unit comprising the portions 2 and 4,'the'windings 3 and 8 or 5 and it may be put into circuit. Grid bias may be suppliedto the control grid of valve Vi from a source of potential, not shown, in series with the selected winding or may be produced by the potential drop in resistor R in the filament lead. Grid bias may be supplied in a like manner to the second high frequency amplifying screened grid valve V2. Valve Vi is coupled to valve V2 through a second similar transformer having primary and secondary portions id and i6 respectively. The arrangement of this transformer is similar to that already described, the primary windings being indicated at i3, i5, and I1, and the secondary windings being indicated at i3, i5, and ii, while the contacts are indicated at C9 C16, and the co-operating switch members at S5 S8.

Valve V2 is coupled to a detector valve V3 50 through a further transformer which, so far as the transformer portion is concerned, is similar to the transformers already described. Mechanically, however, the unit differs from the two transformer units above described in that it comprises in addition to a primary portion 20 and a secondary portion 22, a reaction portion R. The windings on the transformer primary and secondary portions are indicated at l9, 2|, 24, 28; the fixed contacts of these portions are indicated at CIT C24, and the co-operating switch members are indicated at S9 Si2. The reaction portion R, which, as will be seen from Fig' ure 2, is in a mechanical unit with the portions 20 and 22, is provided with windings 23, 25, each appropriate to one wave length range, the said windings terminating respectively in contacts C26, C21 and C25, C28, and co-operating with these contacts are switch members SI 3, S.

The mechanical arrangement of the inductance unit comprising the portions 20, 22- and R, will be apparent from Figures 2, 3, and 4, the said unit being adapted to be rotated in common with the other units by the rotation of a common control knob CK fast on a shaft CS and driving the various mechanical units through bevel wheels, such as BW. A pointer IP is provided to indicate the wave length setting at any particular time.

Reverting to Figure 1, grid bias is applied to the valve V3 from a suitable source of potential, not shown, which is connected at GB2, while grid bias is applied to a low frequency amplifier valve V4 from a suitable source connected at G133.

The common high tension supply point for all four valves is indicated at HT. The signal output terminals are indicated at O, the earth point at E, the common negative point at C OM and the point of application of potential for the screening electrodes of the screened grid valves at SG. Filament heating potential for all the valves is applied between LT+ and COM-, the positive filament lead including a switch LTS and a control rheostat FR.

It will be seen that with this arrangement, it is merely necessary to rotate the knob CK to brin the set from one wave length receiving range to another, while the amount of external wiring is very small, indeed, hardly more than would be the case in a set designed for use on one wave length range only.

In cases in which it is desired to place-adjacent inductance units at a particular angle with relation to one another e. g. at 90, for example,

-to reduce magnetic coupling effects, it ismerely necessary to arrange the mechanical drive from the common knob CK so as to be adapted to this end.

It.will be noted that in Figures 1 and 2, three sets of windings for covering only three wave length ranges have been shown for the sake of simplicity in the said figures. Obviously, however, accommodation may be made for any number of wave length ranges likely to be required in practice.

As has been set forth the amplifier represented in Figure 1 is adapted for use on three wavelength ranges although more wavelength ranges could be used. In any case screening is provided for the inductance devices in the various stages. The screens are indicated by broken lines enclosing the inductance units. It will further be noted that provision is made in Figure l for adapting the amplifier to receive-either continuous wave signals or spark signals. To this end the winding is is tapped and a switch is provided as shown, the circuit being such that when the switch is in its upper position (contact CW) the amplifier is adapted for use for continuous wave reception while when the switch is in its lower position (contact SP) the amplifier is adapted for use for spark reception. I

The invention is obviously capable of considerable detailed variation from the arrangement without departing from the scope thereof. For example, the transformer units, the windings of which may conveniently be wound upon formers of solid insulating material, may be so constructed that each transformer may be removed from the receiver as a unit complete with its bevel wheel which is adapted to be engaged for adjustment purposes by an appropriate bevel wheel on the control shaft CS.

Another and a preferred detail modification consists in providing one or more short circuiting means associated with each transformer unit in such manner that the winding or windings ad- I jacent those actually in circuit when the transformer is in any given position of adjustment is or are short circuited. This preferred arrangement presents the advantage that undesirable resonance in idle windings" are to a large extent avoided if not completely eliminated. Such short circuiting of non-connected windings may be eifected in a variety of simple ways, for example, by providing, as shown in Figures 2a and 3a, stationary bridge pieces SB supported as shown and adapted to co-operate with any or all of the transformer contacts not actually contacting at any given position of adjustment with the contact devices in the circuit proper. Short circuiting means as shown in Figures 2a and 3a may be provided for each set of windings in each unit in each modification of the inductance system.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, Iv

declare that what I claim is:-

1. A multi-range oscillatory energy receiver comprising a plurality of inductance units each having a. plurality of sets of coaxial windings, each set of windings being appropriate to one tuning range, the windings of each set terminating in contact devices adapted to co-operate selectively with appropriate switch members according to the position into which the unit is rotated, means for rotating all of said units simultaneously and equal amounts whereby said units may be moved together into positions in which the windings in circuit are all appropriate to a desired wave length range, and means for short circuiting one or more idle windings on the inductance units.

2. A multi-frequency range tuning device comprising a plurality of sets of coupling inductances of different values, each of said sets of coupling inductances being appropriate to a different frequency range, relatively fixed rotatable supports mounted one within the other for said inductances, contacts connected to said inductances and carried by the outer one of said supports, and fixed contacts adjacent said supports in the path of rotation of said first named contacts, whereby selective connection between said inductances and said fixed contacts may be made as said support is rotated.

3. A multi-frequency range tuning device comprising a plurality of sets of coupling inductances of different values, each of said coupling units scoped supports for said inductances, contacts 13 connected to each 01. said inductances, said conof said supports, and fixed contacts adjacent said support in the path of rotation of said first named contacts whereby rotation of said support produces selective connection between said sets of inductances and said fixed contacts by way of said contacts on said support.

4. In a multi-range tuning device, a plurality of sets of coupling inductances, each of said sets of coupling inductances comprising a primary winding and a secondary winding, and a reaction winding, said windings of each set being coupled and being appropriate to a diflferent frequency range, rotatable supports one within the other for each set of said inductances, contacts connected to each of said windings, said contacts being carried on the periphery of the outer of said supports, and fixed contacts adjacent said supports in the path of rotation of said first named contacts whereby rotation of said support produces selective connection between the windings of said sets of inductances and said fixed contacts.

5. A multi-frequency range tuning device comprising, a plurality of sets of coupling inductances of difierent values, each of said sets of coupling inductances being appropriate to a particular frequency range, relatively fixed rotatable supports mounted one within the other for said inductances, contacts connected to said inductances and carried by the outer one of said supports, fixed contacts adjacent said supports in the path of rotation of said first named contacts, whereby selective connection between the inductances in each set of said inductances-and said fixed contacts may be made as said support is rotated, and conductive elements adjacent said support in the path oi rotation of said first named contacts to short circuit one or more of the inductances not selectively connected with said fixed contacts.

6. A multi-frequency range tuning device com prising a plurality of inductances of different in ductive values, each of said inductances being appropriate to a particular frequency range, a

.rotatable support for said inductances, contacts connected to each of said inductances and carried by said support, fixed contacts adjacent said support in the path of rotation of said first named contacts, whereby selective connection between each of said inductances and said fixed contacts may be made as said support is rotated, and conductive elements adjacent said support in the path of rotation of said first named contacts to short circuit one or more of the inductances not connected with said fixed contacts.

"I. A multi-frequency range tuning device comprising a plurality of tuning inductances of difierent inductive values, each of said tuning inductances being appropriate to a particular. fre quency range, a cylindrical rotatable support for said inductances, contacts on the periphery of said support, connections between the inductances carried by said support and said contacts, fixed contacts adjacent said support in the path of rotation of said first named contacts, whereby selective connection between each of said inductances and said fixed contacts may be made as said support is rotated, and conductive elements adjacent said support in the path of rotation 01 said first named contacts to short circuit one or more of the inductances. I V

8. A multi-irequency range tuning device comprising a plurality of sets of tunable coupling inductances 0! different values, each of said sets of coupling inductances comprising a pair of coaxial windings, the pairs of windings each being appropriate to a diiferent frequency range, a rotatable support for said sets of inductances, contacts connected to each winding of each set of in-- ductances, said contacts being carried on the periphery of said support,. fixed contacts adjacent said support in the path of rotation of said first named contacts whereby rotation of said support produces selective connection between said sets of inductances and said fixed contacts by way of said contacts on said support, and conductive elements located in the path of rotation of said contacts on said supports to short circuit the sets of inductances not selected.

9. A mum-frequency range tuning device comprising a plurality of sets of coupling inductances of different values, each of said coupling inductances comprising co-axial windings and being appropriate to a difierent frequency range, a rotatable support for all of said inductances, contacts connected to each of said sets of inductances, said contacts being carried on the periphery of said support, fixed contacts adjacent said support in the path of rotation of said first named contacts whereby rotation of said support produces selective connection between said sets oi inductances and said fixed contacts by way of said contacts on said support, conductive elements located in the path of rotation of said contacts on said supports to short circuit the inductances not selected, and means for rotating said support,

iii. In a multi-range tuning system, a rotatable support, a plurality of sets of coupling inductances mounted on said support for rotation with said support, each set of coupling inductances comprising a plurality of windings each adaptedv to interconnect adjacent stages in a cascaded wave relay, contacts connected with said windings and extending from the periphery oi said support, there being a set of contacts for each winding in each set of coupling inductances, fixed contacts mounted adjacent the periphery of said support whereby rotation of said support selectively connects the windings of said sets of coupling inductances to said fixed contacts, and conductive means mounted adiacent said support for short-circuiting one or more of the windings not connected to said aforesaid fixed contacts.

ii. In a multi-range tuning system, a rotatable cylindrical support, a plurality of sets of coupling inductances mounted on axes parallel with the axis of said support for rotation with said support, each set of coupling inductances comprising a plurality of windings each adapted to interconnect adjacent stages in a cascaded wave relay, contacts connected with said windings and extending from the periphery of said-support,

there being a set of contacts for each winding in,

each set of coupling inductances, and fixed contacts mounted adjacent the periphery of said support whereby rotation of said support selectively connectsthe windings of said sets of coupling inductances to said fixed contacts.

12. In a multi-range tuning system, a rotatable support, a plurality of sets of coupling elements set of windings and extending from the periphery of said support, and fixed contacts mounted adjacent the periphery of said support whereby rotation of said support selectively connects windings of said sets of coupling elements to said inxed contacts.

switch device operable selectively to connect and disconnect each coil as desired for operation as a part oi the set and selectively to prevent any coil not in operation from interfering with the coil in operation.

15. In a radio set, a plurality of coils each adapted for use in connection with the tuning of the set over a diflerent range of signals, and a switching device operable selectively to connect and disconnect each coil as desired for operation as a part of the set and selectively to short circuit one or more coils not in operation to thereby prevent the same from interfering with the coil in operation.

FRED WOODS. 

